By NewsDesk @infectiousdiseasenews
The majority of those infected with the coronavirus had neutralizing antibodies after more than a year, according to a study by the National Institute for Health and Welfare published preprint in MedRxiv. A recent study looked at the persistence of antibodies produced by a diseased coronavirus disease six months and a year after infection.
As many as 97% of subjects had IgG antibodies recognizing the coronavirus peak protein one year after infection. Although antibodies were detected in many, their levels after one year were about one-third lower than they had been six months after infection.
“Investigating antibody levels after coronavirus disease provides important information that also helps assess the protection and duration of vaccines,” says Merit Melin , THL’s research manager.
The subjects had been diagnosed with a coronavirus infection in the spring of 2020. The infection had been confirmed by a PCR test, after which they had not been diagnosed with a new coronavirus infection and had not received a coronavirus vaccine prior to sampling.
A total of 1292 individuals were tested for antibodies six months after infection and 367 individuals one year later. Fifteen percent of those surveyed after six months and 13 percent of those surveyed after one year had had a serious coronavirus infection requiring hospitalization.
Patients with severe disease requiring hospitalization had significantly higher levels of antibodies than those with mild disease. All patients with severe disease still had neutralizing antibodies after one year.
“The results of the study show that after coronavirus infection, neutralizing antibodies and protection against a new infection are maintained for a long time if the amount of antibodies was initially high,” says Melin.
The study also looked at the ability of the antibodies to neutralize altered viral forms. The amount of neutralizing antibodies against the Alpha variant was slightly lower compared to the virus strain and significantly lower against the Beta and Delta variants. Especially in patients with mild disease, the level of antibodies against viral variants was reduced.
Infections caused by viral variants have also been reported in vaccinees after both single and double vaccine doses. However, vaccines provide good protection against a serious form of the disease caused by viral variants.
“The protection against serious disease that results from infection or vaccination is based not only on antibodies but also on cell-mediated immunity and memory cells that activate and produce antibodies when they encounter a pathogen,” Melin explains.
Note: This study has NOT been peer-reviewed
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